Which of the following are aromatic?

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(A) To determine if a compound is aromatic,it must satisfy $H$ückel's rule ($4n+2$ $\pi$ electrons),be planar,and have a continuous cyclic conjugation

Vedclass · Accepted Answer

$B$ and $D$ only

Vedclass · Answer

(A) To determine if a compound is aromatic,it must satisfy $H$ückel's rule ($4n+2$ $\pi$ electrons),be planar,and have a continuous cyclic conjugation.$A$: This is $1,4$-dihydronaphthalene. It is non-aromatic because it is not fully conjugated.$B$: This is styrene (vinylbenzene). It contains a benzene ring,which is aromatic.$C$: This is $[10]$-annulene. It is non-aromatic due to steric hindrance between internal hydrogen atoms,which prevents the molecule from being planar.$D$: This is $[14]$-annulene. It is aromatic as it follows $H$ückel's rule ($n=3$,$4(3)+2 = 14$ $\pi$ electrons) and is planar.Thus,$B$ and $D$ are aromatic.

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